Printability tester

ABSTRACT

A MACHINE FOR TESTING THE PRINTABILITY OF PAPERS, INKS AND PRINTING PATTERNS, ESPECIALLY IN GRAVURE PRINTING, WHEREIN A ROTATING IMPRESSION ROLL IS DISPLACEABLE TO PRESS A LOOPED PAPER SAMPLE BRIEFLY AGAINST A ROTATING PRINTING CYLINDER SO AS TO IMPRINT A SINGLE PATTERN ON THE SAMPLE, IS PROVIDED WITH AN ECCENTRIC SLEEVE MOUNTING FOR THE IMPRESSION ROLL SHAFT AND WITH ACTUATING AND CONTROL MECHANISMS WHICH ACT UPON THE SLEEVE TO DISPLACE THE ROLL IN PRECISE, SPEED-INDEPENDENT RELATIONSHIP TO THE ROTATIONAL POSITION OF THE PATTERN TO BE TEST PRINTED. THE SLEEVE MOUNTING PROVIDES FOR PRECISE ADJUSTMENT OF THE IMPRESSION ROLL PRESSURE. A FORCE-LIMITING COUPLING PROTECTS AGAINST PRESSURE OVERLOADS. CONTROLS ASSURE A SINGLE IMPRINT IRRESPECTIVE OF THE MOMENT OR THE DURATION OF MANUAL INITIATION OF A PRINTING TEST.

Sept. 20, 1971 w. F. HUCK PRINTABILITY TESTER Filed June 25, 1969 4 Sheets-Sheet 1 I, EIH-EEE INVENTOR WILLIAM F. HUCK Y ATTOR Sept. 20, 1971 w. F. HUCK 3,605,615

PRINTABILITY TESTER Filed June 25, 1969 4 Sheets-Sheet 3 FIG..3

INVENTOR WILLIAM F. HUCK ATTORNEY Sept. 20, 1971 w HUCK 3,605,615

PRINTABILITY TESTER Filed June 25, 1969 4 Sheets-Sheet 4 v S I 630 I494 INVENTOR WILLIAM F. HUCK ATTOR EY United States Patent 3,605,615 PRINTABILITY TESTER William F. Huck, 285 Gregory Road, Franklin Lakes, NJ. 07417 Filed June 25, 1969, Ser. No. 836,292 Int. Cl. B41f 9/04 US. Cl. 101-153 11 Claims ABSTRACT OF THE DISCLOSURE A machine for testing the printability of papers, inks and printing patterns, especially in gravure printing, wherein a rotating impression roll is displaceable to press a looped paper sample briefly against a rotating printing cylinder so as to imprint a single pattern on the sample, is provided with an eccentric sleeve mounting for the impression roll shaft and with actuating and control mechanisms which act upon the sleeve to displace the roll in precise, speed-independent relationship to the rotational position of the pattern to be test printed. The sleeve mounting provides for precise adjustment of the impression roll pressure. A force-limiting coupling protects against pressure overloads. Controls assure a single imprint irrespective of the moment or the duration of manual initiation of a printing test.

This invention relates to improvements of a machine or instrument called a printability tester, the purpose of which is to enable reliable evaluations of the printing properties of inks, papers or other printing materials by tests of them which simulate commercial printing operations yet can be carried out efficiently on a laboratory scale. The invention is particularly beneficial for testing the stability of various materials for use in high speed rotogravure printing.

A mechanism to serve as such a printability tester, proposed heretofore, involves basically the provision of a rotary gravure cylinder and an impression roll, each on a rotary support protruding from the front of a box frame, with an ink fountain, a doctor blade and a predoctor coacting with the engraved surface of the cylinder and certain actuating, control and drive elements coacting with the rotary supports. The impression roll is normally to be out of engagement with the gravure cylinder, and a paper guide is arranged adjacent to the impression roll so that a paper sample in looped form placed about the guide will extend through a gap normally present between the impression roll and the cylinder. The cylinder and roll are to be kept in continuous rotation, with continuous inking and doctoring of the printing elements of several image areas, or printing patterns, engraved in circumferentially spaced portions of the surface of the cylinder. An imprint of a single selected pattern is to be made on the paper sample in a portion of a single revolution of the cylinder by displacement of the impression roll on an eccentric support into and from a printing position in which the roll will press the paper sample against the surface of the rotating gravure cylinder for a brief interval.

The proposed printability tester, although effectual as to certain basic relationships of its elements, has shown a variety of deficiencies which prevent it from fulfilling the purpose above stated.

Among these deficiencies are that the mechanism is susceptible to differences of action at different rotational speeds and is not sufficiently reliable for repeatedly printing the whole of a certain selected pattern on successive paper samples; it lacks adequate provision for regulation of the impression roll pressure to suit varied test conditions; and it can be overstressed by working with 3,605,615 Patented Sept. 20, 1971 a sample of relatively thick sheet material if the samples being test printed one after another differ very much in thickness or compressibility.

The principal object of the present invention is to provide an improved printability tester which will overcome such deficiencies and fulfill successfully the purpose above stated.

To this end, according to the invention, a rigid rotary shaft carrying the impression roll on its forward end is supported rotatably and eccentrically in a sleeve which in turn is held rotatably within a bearing ring mounted in the frame of the machine, a backward part of this shaft being provided with drive means for rotating it continuously in synchronism with a main shaft carrying the printing cylinder in juxtaposition to the impression roll, and elements for displacing the impression roll so as to cause a single imprinting of a selected pattern on each paper sample-including a driven member turnable with the sleeve, a drive member rocked about the axis of rotation of the sleeve in synchronism with the rotation of the printing cylinder, means for connecting those members together to turn the sleeve and means for activating and inactivating such connecting means--are arranged to operate in constant coordination with the rotational positions of the selected pattern on the surface of the printing cylinder.

Thus, the improved machine can operate reliably to give an imprint of the selected pattern on each paper sample, at any rotational speed that may be chosen for the printing.

According to another feature of the invention, the sleeve eccentrically supporting the shaft of the impression roll is itself supported eccentrically in a bearing ring which is turnable in the stationary frame, and means are provided for turning the bearing ring so as to alter the distance between the respective axes of the sleeve and the printing cylinder and thus secure precise adjustments of the pressure to be applied by the impression roll against the paper or other sheet material to be imprinted.

According to another feature of the invention, the above mentioned driven member turnable with the sleeve is connected with the sleeves through force-limiting means which prevent the torque transmitted by the said connecting means, and thus the pressure applied by the impression roll in printing position, from exceeding a predetermined value. By simply pre-selecting the magnitude of this maximum turning force, the pressure to be applied by the impression roll can be readily limited so as to protect the machine against being overloaded when a paper sample used in thicker or more rigid than that for which the impression roll is pre-set.

Still other important features of the invention reside in its provisions for ensuring that the printing of each paper sample will begin only in proper relation to the approach of a selected printing pattern to the impression roll and that the impression roll will be returned from printing position to normal idle position when that one pattern has moved beyond it, irrespective of the printing speed used and of the moments of manual actuation if a printing test by a person attending the machine.

The above mentioned and other objects, features and advantages of the invention will be apparent from the following detailed description and the accompanying drawings of an illustrative embodiment of the improved printability tester. In the drawings:

FIG. 1 is a front elevational view of the printability tester, some parts being broken away and some shown in section;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a vertical cross-sectional view taken approximately along line 3-3 of FIG. 2;

FIG. 4 is an enlarged cross-sectional view of a portion of the mechanism, taken approximately along line 4-4 of FIG. 2;

FIG. 5 is an enlarged side elevational view of an adjustable doctor mechanism provided for the machine;

FIG. 6 is a diagrammatic view of the one-print actuating mechanism in position to begin a printing impression; and

FIG. 7 is a diagrammatic view of the same mechanism acting to end an impression.

By reference to FIGS. 1, 2 and 3 it will be seen that the improved machine includes basically a rotary printing cylinder 10 having a mating impression roll 20 disposed above it at the front of a supporting frame F, with an ink fountain 40, pre-doctor device 50 and doctor blade 60 arranged to coact with the surface 12 of cylinder 10- and a paper guide 70 arranged about the impression roll to receive and support a band S of paper or other flexible sheet material, in looped form, which is placed over this guide and thus about the impression roll 20 so as to extend freely through a gap G normally present between the cylinder 10 and roll 20.

The printing surface '12 is formed with at least one engraved printing pattern, or intagliated image area, such as indicated diagrammatically at P in FIG. 3. Usually there will be three different printing patterns spaced apart circumferentially of the cylinder 10, so that any one of the three may be selected for use in printability tests.

The ink fountain 40 includes a trough 41 to hold a pool of ink in which the printing surface 12 will be immersed. The trough 41 is secured tightly yet removably against the outer face of frame F by locking screws 42 and 43 which engage, respectively, into support studs 44 and 45 mounted in frame members F1 and F2. Blades 46 and 47 and doctor structures at 60 close most of the gap be tween the top of trough 41 and the cylinder 10'. The top of the trough also contains spring pressed side cheeks 47a and 47b (FIG. 3) which bear against the opposite side portions of the printing cylinder to prevent ink from whirling up along its sides when the cylinder is running at high speed. The fountain 40 can be filled through an open mouth 48a and emptied through a drain valve 48b. It contains a baffle 49a and side wall 49b to keep ink from splashing out of the fountain. By virtue of the side cheeks and related structures of the fountain 40, the fountain is sealed over the ink pool so that little or no evaporation of ink solvents will occur and the ink will be maintained at the proper viscosity during printing.

The pre-doctor '50 is a blade mounted on a fixed support 52 with its forward edge spaced a slight distance away from the printing surface 12, and having a tail portion 54 directed downward toward the outer side of bafiie 49a. The pre-doctor blade limits the thickness of the ink film that can be carried on the surface of the printing cylinder to the location of the doctor 60, and diverts the excess ink back and down along tail portion 54 and the outer side of 'bafiie 49a into the ink supply held in the fountain trough 41.

The doctor 60 includes a blade 61 mounted through adjustable holders 62 and 63 on a shaft 64 which is turnable and slideable relative to the frame. An arm 65 on shaft 64 is connected with a tension spring 66 extending from a support pin 67 slidably positioned in a slot in the wide wall of the frame and coacting with a calibrated plate 67a. A hollow stem 68 also connected with pin 67 extends through the top Wall of the frame to a threaded connection with aknob 69 by which the position of pin 67, and thus the stretch and tension of spring 66, may be adjusted. The spring turns shaft 64 so as to hold the edge of the doctor blade against the printing surface 12 with a pressure determined by the tension setting of spring 66. Arm 65, however, is engageable by a rod 65a which will be displaced downwardly by arm 65b on a shaft 65c when a lever arm 65d secured to this shaft in front of the frame is moved clockwise to engage in an OFF detent a. The lever arm 65d thus serves to move the doctor blade to a position where it will remain out of engagement with the printing surface when the machine is not in use, and counter-clockwise movement of this arm releases the doctor mechanism so that the blade 61 will work with the selected pressure against the surface of the printing cylinder.

When the doctor blade 61 is in working position, its edge bearing against the printing surface scrapes off all the ink carried by that surface beyond the pre-doctor 50, excepting only those minute portions of the ink which are held in the recessed image portions of the printing patterns.

The paper guide includes a spring plate member 72 held on several support posts 73 which extend forwardly from the front of the frame F at locations spaced about the impression roll 20. In the normal position of that roll, a loop of paper or other sheet material to be test prined may be slipped readily onto the plate 72, to remain stationary thereon with a part of the sample extending through the gap G. As soon, however, as the impression roll is lowered to press the sample S against the printing surface, the sample will be grasped between and moved with the engaging surfaces of roll 20 and cylinder 10 for as long as the roll remains in printing position, during which interval the sample slides longitudinally about the curved outer surface of guide plate 72.

The impression roll 20 comprises a cylindrical body 21 fixed to the forward end of a rotary shaft 22 and having an elastic cylindrical covering layer 23 of rubber or like material. The shaft 22 extends backwardly through bearing supports 24 and 25 to a backward end 26 having a driven pulley 27 fixed thereto.

The printing cylinder 10 comprises a cylindrical body 11 having an intagliated outer surface 12, and is mounted securely on the forward end of a rotary shaft 13 (FIG. 3). This shaft extends backwardly through bearing 15 and 16 mounted in the frame members F1 and F2, and terminates in a backward end 17 which is connected for rotation with a pulley wheel 18 through an adapter flange 19 keyed to the shaft end 17 at 19a and through screws 1% which releasably interconnect flange 19 and wheel 18.

The rotary drive system for the cylinder 10 and roll 20 includes the pulley Wheels 18 and 27 secured to the backward ends of shafts 13 and 22 and an endless belt 28 which passes about the outer surface 27a of wheel 27 and the aligned surface 18a of wheel 18, as seen in broken lines on FIG. 2, and is trained and tensioned to the desired working position by idler pulleys 29a and 291), the latter of which is positioned adjustably by a belt tensioning device 29. The belt 28 interconnects the shafts 13 and 22 so that they will be driven in unison and, preferably, with the surface speed of the impression roll 20 slightly lower than that of the printing cylinder 10. The driving of the system is effected by a motor mounted on a spring support 81 secured to the frame of the machine. The motor shaft carries a pulley 82 driving a V-belt 83 trained about a driven V-belt pulley 18b of wheel 18 on the shaft of the printing cylinder.

It will be evident that when motor 80 is running the printing cylinder and the impression roll will both be rotated, yet no printing action will occur while the impression roll remains in its normal position with a gap present between its surface and the printing surface 12.

In order reliably to produce a single imprint, or impression, of a selected printing pattern of surface 12 upon successive paper samples placed over the paper guide 70, the impression roll in each printing test is to be displaced to and from a position of engagement against the printing surface at moments precisely related to the rotational position of the particular pattern to be printed, and is to be held briefly in such engagement with a pressure suited to the nature of the samples being test printed. To this end, the machine is further constituted with the actuating and control mechanisms now to be described.

As seen in FIG. 2 and FIG. 4, the shaft 22 of the impression roll is supported on its bearings 24 and 25 both rotatably and eccentrically within a sleeve 30 which extends (FIG. 3) from a location in front of the frame F backwardly through bearings 31 and 32 to a backward end portion 33 located near the pulley wheel 27. Sleeve 30 has an eccentric internal configuration and is cylindrical externally so as to be rotatable in its bearings, about their common axis at A, within the confines of a normally stationary bearing ring 34 which holds the sleeve bearings 31 and 32 in the frame members F1 and F2.

It will be evident that a small turning movement of the sleeve 30 in the counter-clockwise direction (FIG. 2) on axis A will displace the shaft 22 and the impression roll 20 thereon downwardly for forcible engagement of the roll surface against the printing cylinder, while the return movement of the sleeve will bring the impression roll back to its normal idle position.

The pressure to be applied by the roll 20 against printing surface 12 in the downward, or printing, position of the roll depends upon the given diameters of roll 20 and cylinder and the distance between their respective axes of rotation. In order that this pressure may be adjusted precisely to give any desired printing condition, the sleeve 30 is supported eccentrically in the bearing ring 34, as by providing the latter with an eccentric internal configuration where the sleeve bearings 31 and 32 are seated in it, and the bearing ring is itself supported turnably on cylindrical bearing surfaces 34a and 34b of the frame members F1 and F2. As seen in FIG. 1 and FIG. 3, an arm 35 fixed to an upper part of ring 34 1S pivotally connected by pin 35a with a threaded coupler 36. A screw 37 threaded into the coupler extends from it through an opening in side portion 38 of the frame to a calibrated knob 38a provided outside the frame F for turning the screw. A spring 39 compressed between frame portion 38 and the end of coupler 36 normally holds the arm 35 and bearing ring 34 in a fixed pos1t1o n determined by the setting of screw 37. Whenever 1t 1s desired to adjust the pressure to be applied by the 1mpression roll in printing position, the desired adjustment can be effected with precision by simply turning the calibrated knob 38a and screw 37 so as to turn the bearing ring 34 in the frame and thereby displace the axis A of the sleeve by a desired small distance toward or away from the axis of rotation of the printing cylinder.

For the required displacements of the roll in part of a single revolution of the printing cylinder, the sleeve 30, as seen in FIGS. 2, 3 or 4, is provided with a turnable member 90 which is suitably connected with sleeve end portion 33 to move therewith about its axis A; and a drive member 100 in the form of a ring loosely surrounding the sleeve and provided with a downwardly extending rocker arm 101 is arranged to be rocked continually about the sleeve axis in synchronism with the rotation of the printing cylinder. The drive member 100 and turnable member 90 are normally disconnected from one another so that the continual rocking movements of member 100 will have no effect. These members, however, are provided with normally inactive means, such as a pawl-like connector 92 pivoted on an car 91 of member 90 to coact with an abutment 102 rocking with member 100, for connecting them together to turn the sleeve 30 on its axis and thus displace the impression roll into printing position.

When the connector 92 is inactive, as it normally is because positioned outside the path of rocking movement of abutment 102 as seen in FIG. 2, the turnable member 90, sleeve 30 and impression roll 20 are held at their normal idle position by suitable means such as a heavy tension spring 93 which is anchored at one end, as at 94, to the machine frame and has its other end connected at 95 to an arm 96 protruding from member 90 at a location away from the ear 91. A nose 97 on arm 96 abuts against a fixed stop 98 to limit the idle position to which member and the sleeve are held by spring 93.

When the connector 92 is shifted into the path of abutment 102, a counter-clockwise turning of drive member 100 and abutment 102 will produce a corresponding movement of member 90 and sleeve 30 about the axis A, with a corresponding extension of the tension spring 93; and when the connector 92 is returned to its normal inactive position, the spring 93 immediately returns member 90, sleeve 30 and roll 20 in clockwise direction (as viewed in PIE. 2) to their idle position.

The rocking movements of drive member 100 for displacement of the impression roll are produced in constant synchronism with the rotation of the printing cylinder by means of a cam follower 104, comprising rollers 104a and 104b fixed to the end of rocker arm 101, and a cam track 105 comprising endless rails 105a and 105b engaged by those rollers.

The cam track rails are integrally fixed to the pulley wheel 18 for rotation therewith. The track which they form has a low region, nearer to the axis of shaft 13, by which the cam follower and drive member 100 are turned to their extreme clockwise position, as seen in FIG. 2. The track slopes from the low region into a high region 106, farther from that axis, by which the follower and member 100 are turned to and held briefly in their extreme counter-clockwise position. The reach of the high region 106 of the cam track is made sufficient to exceed the angular distance encompassed by each printing pattern in the surface of the printing cylinder 10, and the wheel 18 is so oriented relative to shaft and cylinder 10 that the high region 106 will begin to position the cam follower as a certain printing pattern approaches the nip of the impression roll 20 and will leave the cam follower when that pattern has passed beyond the impression roll.

The particular printing pattern so related to the position and operation of the cam track can be selected as desired by suitably indexing the angular position of the wheel 18 relative to the shaft 13. For this purpose, the screws 19b connecting adapter flange 19 with wheel 18 may be disengaged and the shaft and wheel may then be turned one relative to the other to a new angular position in which the high region of the cam track will span the angular location of the selected pattern on printing surface 12, whereupon the screws are re-engaged with the wheel to secure the parts in this selected relationship.

While as above described the turnable member 90 is connected with the sleeve 30 for movement therewith about axis A, this connection according to a further feature of the present invention is effected through forcelimiting means which serve to prevent the torque transmitted to the sleeve and roll 20 when connector 92 is active from exceeding a predetermined value suitable for protection of the machine against being overloaded, irrespective of the thickness of the test sample S or of other printing test conditions.

As seen in FIG. 2, this force-limiting means includes links 110 and 111 having ends pivotally joined together by a pin 112 on which guide rollers 113 are mounted. The other end of link 110 is pivoted at 114 to arm 96 of turnable member 90. The other end of link 111 is pivoted at 115 to an arm 116 protruding from a ring member 117 which is fixed, as by a key 118, to the backward end portion 33 of sleeve 30. The rollers 113 at the joint between the links bear constantly against guide surface 120 on a lever 122 which is fiulcrumed on pin 123 and is constantly urged against the rollers 113 by a tension spring 124 having one end secured at 125 to the frame and having its other end secured at 126 to the upper end of lever 122. A guide surface 127 on box 128 fixed to the frame limits displacement of the rollers 113 and links 110 and 111 in the direction toward the sleeve 30.

It will be evident that under normal working conditions a turning movement imparted to member 90 and its arm 96 by enagement of abutment 102 with connector 92 will be transmitted directly through the links 110 and 111 to the ring member 117 keyed to the sleeve, with displacement of the links and rollers 113 along and between the confronting guide surfaces 120 and 127 of lever 122 and box 128. On the other hand, if the resistance to displacement of the impression roll by turning movement of the sleeve should at any time be so great that the thrust of the links and rollers 113 against surface 120 overcomes the force of spring 124, then the lever 122 will be displaced by the rollers 113', with outward movement of the joined ends of the links, so as to limit the torque transmission of the links, and thus the stress applicable to the roll displacing mechanisms, to a maximum value determined by the tension of spring 124.

The initiation of a printing test by use of the machine can be effected at any time, with the drive motor running and the ink, the doctor and a paper sample in place, by manual or other movement of a suitable actuating device. A suitable manual activator comprises a push button 130 on the outer end of a rod 131 extending slidably through a bearing 132 in frame F and connected with other parts as described hereinafter.

In order reliably to ensure that a complete single impression of the selected printing pattern only will be printed on the paper sample in each test, the test actuating means of the improved machine is provided not only with such manually operable means for initiating a printing test but also with elements which are positioned by the rocking drive member 100 so as to cause the activation and inactivation of the means for interconnecting members 90 and 100, such as shiftable connector 92, and thus the required displacements of the impression roll, to take place only in proper relation to the rotational position of the pattern to be printed, irrespective of the moment of operation of the push button 130 or like device.

As seen in FIG. 2, the connector 92 has an arm end 92a to be engaged by abutment 102 and, at the opposite side of its pivot ear 91, has an arm 92b which normally is held displaced toward sleeve 30 against the force of a spring 920 compressed between arm 92b and member 90, so that end 92a lies outside the path of movement of abutment 102.

The connector is normally held in this inactive position by a retainer 140 which is pivoted on frame pin 141 and carries a cam roller 142 bearing against the outer side of arm 92b to hold this arm depressed. Retainer 140' also has an arm 143 at the opposite side of its pivot, which arm carries a roller 144 at its end and normally is disposed so that this roller lies just outside the path of movement of a pusher element pivoted at 107a to an arm 103 on the rocking drive member 100.

A tension spring 145 anchored to the frame F constantly urges the retainer 140 in clockwise direction as viewed in FIG. 2,, to bring it, when it is released, from its normal latching position to a position in which the connector 92 will become active to turn the sleeve 30' and displace the impression roll into printing position. The spring 145, however, is normally kept ineffectual by a latch member 146 having a first notch 146a engaged with the end of retainer 140 so as to hold the latter in its latching position With roller 142 depressing arm 92b of connector 92. The latch member 146 also has a stop notch 146i) stepped away from notch 146a, which will receive the end of retainer 140' when the latter is released.

The latch member 146 is pivoted on frame pin 147 and has an outer arm 148 formed with a notched end that normally is engaged by nose 149a of a pawl 149 pivoted to arm 150a of a bellcrank lever 150. Lever 150 also is pivoted on frame pin 147, and its end 1501; is connected by pivot pin 131a with the inner end of push rod 131. Thus, an inward movement of rod 131 by push button 130 turns the lever 150, pawl 149 and latch member 146 as a unit in clockwise direction about pin 147 and. moves notch 146a of the latch member free of the end of retainer 140, to enable a releasing movement of the retainer by spring 145 with attendant shifting and activation of connector 92.

This potential releasing movement of the retainer, however, does not actually occur unless the printing pattern to be test printed is in a proper location of approach to the impression roll 20, that is, unless the cam follower 104 is in the low region of the cam track which, as previously stated, has a pre-set angular orientation relative to the position of that pattern. This limitation upon the release of the retainer is secured by means of coacting position control elements 160 and 161 which are fixed respectively to the retainer and to an arm 108 on drive member 100. These elements are advantageously formed as leaf spring members having mounting portions secured respectively to the base of retainer 140' and the end of arm 108 and having respective end portions which protrude freely from the mountings and are then turned back toward them, in opposite directions, so as to form tongues 160a and 161a capable of interfitting one against another.

When the drive member 100 is in its position given by the low region of the cam track, the end of spring tongue 161a is disposed slightly away from the end of spring tongue 160a; so a releasing movement of latch member 146 at that moment will allow the retainer 140 to be moved by spring from its latching position to a released position in which its end will fall into the stop notch 1461) of member 146, as it is seen in FIG. 6. On the other hand, if the pattern to be imprinted is not in a proper location of approach to the impression roll, the drive member 100 will be in a position displaced counter-clockwise from that seen in FIG. 2, with spring tongue 161a engaged over spring tongue a so as to prevent the releasing movement of retainer 140 until such time as the rotation of the printing cylinder has again brought the selected pattern into a proper location of approach to the impression roll with corresponding location of the cam follower in the low region of the cam track.

Although the push button 130 often will be depressed to release the latch member 146 at a moment not corresponding to the disengaged condition of the position control elements 160 and 161, that condition will occur quickly due to the high speed of rotation of the printing cylinder, whereupon the outward movement of the end of retainer 140 into stop notch 14Gb takes place immediately. The stop notch 14Gb then holds the latch member in released position, notwithstanding that it is constantly urged toward latched position by a tension spring 1460.

As the retainer 140 moves to released position the connector 92 is shifted clockwise by spring 92c to place i s end 92a in the path of abutment 102. Then the ensuing counter-clockwise movement of drive member 100, as caused by transition of the cam follower from the low region to the high region of the cam track, acts through turnable member 90 and the parts moving with it to displace the impression roll 20 into printing position.

The impression roll 20 then is held in printing position during the limited interval of engagement of the cam follower 104 by the high region 106 of the cam track, causing a full imprint of the selected printing pattern to be made on the paper sample S. Immediately as that pattern passes beyond the impression roll, the cam track displaces the follower and drive member 100 clockwise back toward the low-cam position shown in FIG. 2. In the course of this movement the retainer 140 is returned to its latching position, thus shifting connector 92 away from abutment 102, by the action of pusher element 107 on arm 103 against roller 144 on arm 143 of retainer 140, and the heavy tension spring 93 immediately displaces the impression roll back to its normal idle position away from the printing surface 12.

That resetting action of the pusher element 107 results from the fact that the preceding clockwise releasing movement of retainer 140 for activation of the connector placed roller 144 in the path of oscillation of element 107. The pusher element 107 has a cam end 107k and has an arm 107c constantly engaged by oppositely acting leaf springs 109a mounted on an arm portion 109 of member 100. The springs 109a enable the cam end 107b to be pivoted inward by and slid under roller 144 as it is moved counterclockwise with drive member 100, the re tainer 140 being in released position. Upon the return, clockwise movement of member 100, however, the arm 103 carries cam end 1071; into direct thrusting engagement against roller 144, so that element 107 then pushes that roller and the retainer 140 counter-clockwise, returning the retainer to its latching position. The latch notch 146a then is pulled over the end of the retainer by spring 146a to reset the retainer in latching position with its roller 142 holding connector 92 inactive.

It will be evident that if the lever 150 and latch member 146 continued to act as a unit, an attendant holding the push button 130 depressed longer than momentarily might cause more than one impression to be imprinted on the paper sample, as the latch member 146 might thus keep retainer 140 released until another activation of connector 92 causing another displacement of the impression roll had occurred.

That possibility is avoided by the action of the pawl 149 pivoted on arm 150a of the lever 150. As lever 150 approaches the limit of its clockwise movement by push button 130 and rod 131, a tail 14% on pawl 149 engages a fixed pin 1490 which turns the pawl so as to lift its nose 149a out of the notched end of arm 148 of the latch member, and the lever then moves nose 149a over that notched end. The nose remains there, leaving the latch member 146 free to be returned to latching position by Spring 146c when retainer 140 is moved counter-clockwise, for as long as the push button 130 is held depressed. Upon release of the push button, however, the lever 150 and rod 131 are returned to normal position by a spring 152 acting upon lever arm 150a, and the pawl 149 is returned by spring 153 to its normal position of engagement of nose 149 in the notched end of arm 148.

Accordingly, the improved machine operates reliably to make a single printed impression of the selected pattern on the paper sample in each printing test, irrespective of the moment when the push button 130 is pressed to initiate a printing test and of any delay in releasing the push button.

The doctor blade 61 is continually displaced axially relative to the printing surface 12 during the operation of the machine. For this purpose, a suitable drive mechanism, not shown in detail, translates th rotation of a cross shaft 172, driven from shaft 13 through worm 170 and worm gear 171, into reciprocating movement of the sliding shaft 64 of the doctor mechanism 60.

The doctor blade holders 62 and 63 provide for dual angular adjustments of the blade relative to the shaft 64, so that the blade may be adjusted to any desired angle relative to the printing surface without changing the distance of its edge from the supporting shaft. For this p pose, as shown in FIG. 5, the blade 61 is suitably clamped in holder 62 which fits turnably into cupped portion 63a of holder 63 and is held therein at any desired angular setting by screws 62a which pass into holder 62 through a slot in portion 63a and engage clamps 62b thereover. Similarly, holder 63 has an upper cupped portion 63b which fits turnably over the shaft 64 and is held at any desired angular setting thereon by screws 64a which pass into the shaft through a slot in portion 63b and engage clamps 64b thereover. Index marks on holder 62, cupped portions 63a and 63b and the end of shaft 64 enable the desired adjustments to be made readily in proper relationship one to another.

Although an illustrative embodiment of the present invention has been described in detail herein with reference to the accompanying drawings, it is to be understood that the invention to be protected is intended to be defined by the appended claims and is not limited to particulars of the illustrated embodiment except as may be required for fair construction of the terms of the claims.

What is claimed is:

1. Apparatus for testing printability, including a rotary cylinder having a printing pattern on its surface, means for inking the printing elements of said pattern, an impression roll normally positioned out of engagement with said surface, respective shafts carrying said cylinder and said roll thereon and mounted in a frame for rotation on parallel axes, drive means for continuously rotating said shafts, and means operable 'within a single revolution of said cylinder for displacing said roll into and holding it in engagement with said surface so as to press, and to cause an imprinting of said pattern upon, a sample of sheet material between said surface and said roll, and then returning said roll to normal position; wherein the last mentioned means comprise a sleeve having the shaft carrying said roll supported rotatably and eccentrically therein,

a bearing ring holding said sleeve rotatable therewithin to displace said shaft, said ring normally being stationary in said frame,

a turnable member connected with said sleeve for movement therewith about its axis of rotation,

a drive member rocked about said axis in synchronism with the rotation of said cylinder,

normally inactive means for connecting said members together to turn said sleeve on said axis,

and actuating means including elements positioned by said drive member for activating said connecting means to turn said sleeve so as to press said roll against said surface as said pattern approaches and passes said roll and for inactivating said connecting means and causing return of said sleeve, shaft and roll to normal position when said pattern has passed said roll.

2. Apparatus according to claim 1, said sleeve being supported eccentrically in said bearing ring, said ring being turnable in said frame, and means for turning said ring therein to alter the distance between the axes of said sleeve and said cylinder and thereby precisely adjust the pressure to be applied by said roll against the material to be imprinted.

3. Apparatus according to claim 1, said turnable member being connected with said sleeve through force-limiting means which prevent the torque transmitted by said connecting means and thus the pressure of said roll against said surface from exceeding a predetermined value.

4. Apparatus according to claim 3, said force-limiting means including pivotally joined links respectively pivoted to arms fixed to said turnable member and said sleeve, a movable member limiting the path of the joint of said links, and means yieldably holding said movable member in said path with a predetermined force.

5. Apparatus according to claim 1, said connecting means comprising a shiftable connector carried by said turnable member and means also carried thereby for moving said connector to an active position in which it will be engaged by a part of said drive member to turn said sleeve and said roll into printing position, said actuating means including means normally holding said connector displaced out of the path of rocking movement of said part.

6. Apparatus according to claim 5, said holding means including a retainer movable between a latching position in which it holds said connector so displaced and a position in which it is released from said connector, means biasing said retainer toward said released position, and a latch member normally engaging said retainer to hold it in latching position, said actuating means also including means operable manually to displace said latch member out of such engagement.

7. Apparatus according to claim 6, and reset means carried by said drive member and coacting with means on said retainer in a certain phase of the rocking movernent of said drive member to return said retainer from released position to latching position and thereby inactivate said connecting means, said turnable member having means connected therewith for thereupon turning it and said sleeve in the direction to return said roll to normal position.

8. Apparatus according to claim 1, said actuating means including means normally holding said connecting means inactive, means to initiate release of said holding means for activation of said connecting means, and position control means including an element positioned by said drive member to prevent such release except at a rotational position of said cylinder in which said pattern has the desired location of aproach to said roll.

9. Apparatus according to claim 8, said position control means including leaf spring members respectively fixed to said separate member and a partof said holding means, said spring members having interfitting end portions which disengage at said rotational position of said cylinder and which engage together to prevent release of said holding means at other rotational positions of said cylinder.

10. Apparatus according to claim 1, said drive means including a driven wheel on the shaft carrying said cylinder, said wheel having an endless cam track rotated therewith, said drive member comprising a rocker arm carrying at its end a cam follower running on said track.

11. Apparatus according to claim 10, said cylinder having a plurality of distinct printing patterns spaced apart circumferentially on its surface and its shaft being connected with said Wheel by indexing means whereby the angular position of said cam track relative to said shaft and the position of said roll are selectively related to the location of any one of said patterns desired to be imprinted.

References Cited UNITED STATES PATENTS 2,270,374 1/1942 Kanitz 101-453 2,295,080 9/1942 Grupe 101-157 2,356,315 8/1944 Gudger 101235 2,684,028 7/1954 Toft l01-157 2,719,483 10/1955 Smith 101--245 2,744,464 5/1956 Harless l01'l57 2,873,672 2/1959 Sauberlich et al. 101153 2,932,250 4/ 1960 Kanitz 101245 I. REED FISHER, Primary Examiner US Cl. X.R. 

